Method and device for carrying out metallurgical processes, particularly air refining processes



Jan. 2, 1962 MMEL 3 015,554

R. RU METHOD AND DEVICE FOR CARRYING OUT METALLURGICAi. PROCESSES,PARTICULARLY AIR REFINING PROCESSES Filed April 15, 1958 1 2Sheets-Sheet 1 /3 Fig.1

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METHOD AND DEVICE FOR CARRYING OUT METALLURGICAL PROCESSES, PARTICULARLYAIR REFINING PROCESSES Filed April 15, 1958 2 Sheets-Sheet 2 INVENTORR044 1 fioMm EL iffy 115%! Patented Jan. 2, 1952 3,015,554 METHOD ANDDEVICE FOR CARRYING OUT METALLURGICAL PROCESSES, PARTICULARLY AIRREFINING PROCESSES Roman Rommel, 29 Daberger Weg, Brnhl, Bezirk Koln,Germany Filed Apr. 15, 1958, Ser. No. 728,679 Claims priority,application Germany Apr. 18, 1957 Claims. (Cl. 75-51) This inventionrelates to a method and a device for carrying out metallurgicalprocesses, and it more particularly pertains to a method and a devicefor carrying out air refining processes.

While the known converter processes, as for example, the Thomas andBessemer processes in iron and steel industry are very efiicientprocesses, they have the disadvantage that the quality of the steelproduced by these processes falls increasingly short of the currentrequirements. Moreover, they require a specific composition of the pigiron to be blown and, therefore, limit in many cases the applicabilityof these processes on a wide basis.

By enriching the air with oxygen, if desired up to almost 100%, andchanging over to top blowing, the narrow limits of the composition ofthe raw material in case of the classical converter processes could bewidened to some extent.

In a process which has become known recently, the refining is effectedwith oxygen or oxygen-enriched air in a rotating vessel to achieveobviously a better agitation of the charge. Introducing part of theblast into the bath and the other part above the bath has the efiect ofburning the carbon monoxide formed in the decarburization to form carbondioxide so that a considerable part of the heat thus set free isutilized for the process. A considerable improvement in the quality ofthe blown steel could be achieved with this process.

It has now been found that, in metallurgical processes, as for example,in the air refining process, the success obtainable with respect to thethroughput capacity, the yield and the quality of the finished productis the greater the more uniformly the reaction proceeds throughout thebath with the reacting media rapidly changing their position withrespect to each other and with the finished products of the reactionbeing immediately separated from each other.

In case of the known processes, this condition is met more or lessincompletely. The reaction proceeds only in a limited part of the bathvolume, which makes the condition of the bath irregular. This can bemade up only in part by the motion of the bath which extends by no meansthroughout the bath. Therefore, the throughput, the quality and theyield are absolutely capable of considerable improvements.

In accordance with the invention, the requirement mentioned above islargely met by introducing the reaction media (eg. air, oxygen'enn'chedair or oxygen in case of refining by the blowing process) with uniformdistribution over the bath and by maintaining the bath in a turbulentmotion extending uniformly throughout the contents of the bath. Both theintroduction of the reaction media with uniform distribution over thebath and the uniform turbulence prevailing throughout the contents ofthe bath can be achieved in a particularly simple manner in a bath whichrotates about the vertical axis of the reaction ves sel. In accordancewith the invention, the process of constant agitation of the bath isstill accelerated and intensified by superimposing a second motion onthe bath rotating about a vertical axis, said second motionsubstantially providing a rotation about a horizontal axis. From thegeometrical point of view, the bath as a rotational body is formed by aproducing plane, the path of the center of gravity of which mayapproximately represent the axis about which the bath rotates inaddition. The resultant of both motions represents a spiral line closedin itself and extending horizontally about the vertical axis of the bathand filling out the entire bath space. The turbulence produced withsufficient velocity of the motion provides for a constant vigorous anduniform agitation of the bath.

The horizontal cross-sectional area of the bath space fill usually be ofcircular form. The line of the center of gravity ofthe producingcross-sectional area of the bath will then be a circle of about half thediameter of the bath if the producing plane substantially represents arectangle. In specific cases it may be desirable to give the horizontalcross-sectional area of the bath an elliptic or similar shape ifparticular patterns of motion of the bath are to be obtained or in casethis appears to be useful because of constructional conditions.

The motion of the bath as suggested promotes in a particularly efiicientmanner the constant change between the bath and the slag at theinterface thereof. This change is still aided by the gaseous reactionproducts emerging from the bath and the sucxing effect of the vortex inthe center of the bath surface or at the Wall of the vessel according tothe sense of rotation of the spiral motion.

In accordance with the invention, the turbulent motion of the bath canbe maintained by the energy of flow of the reaction media beingintroduced. By selecting the inlet velocity, the direction and place ofintroduction of the reaction media into the bath, the motion of thelatter is capable of being adapted to the particular course of reaction.By the direct contact of the bath with the reaction media, practicallythe total flow energy of the latter is imparted to the bath and the mostfavorable pattern of motion of the bath is obtained. The reaction mediaused for this purpose are generally in gaseous form such as air,oxygen-enriched air, oxygen or other gases. It is also possible in thismanner to carry out processes with liquid reaction media. Solid reactionmedia present in form of dust or fine grains may be introduced into thebath by means of carrier gases which may also be reaction media. Thus,carrier gases or other gases which do not participate in the reactionact as energy carriers only. In addition, they may also function as heatcarriers when introduced in heated state.

A further feature of the process of the invention relates to theintroduction of fuels into the reaction chamber.

These fuels are completely or partially burned for the purpose ofheating up the charge or/and for supplying the heat requirements of theprocess or/ and for reducing the raw materials or the reaction mediacharged. Gaseous, liquid or solid fuels are suited for this purpose.This measure permits a universal application of the present process. Thefeed materials may be melted down in the reaction chamber andextensively heated before the metallurgical process takes place. In thismanner, the supply of heat is also possible during the metallurgicalprocess if the reaction is not sufiiciently exothermic or if anendothermic reaction is involved. Moreover, the fuels, when completelyor partially burned, permit a reducing 7 action to be exerted on thefeed materials. This reducing action may serve for pretreating oraftertreating the materials charged and'for processing oressimultaneously charged.

Thus, in refining by the blowing process of the invention taken as anexample for further illustration, one is no longer bound to pig irontypes of a given composition. The heat of combustion of the fuelsintroduced is capable of compensating the deficiency of silicon,phosphorus or carbon in the pig iron. It is possible, therefore, toprocess, poor-grade pig iron and steel scrap. The process may also beconducted so as to reduce additions of scale or iron ores to formmetallic iron. A further advantage in accordance with the invention isobtained by the fact that reaction media, fluxes, alloying additionsand/or ores present in fine-grained or dustlike form can be introducedinto the reaction chamber by means of gaseous reaction media or inertgases functioning as carrier gases. Due to their small particle size anduniform distribution, they are very rapidly melted down and dissolved inthe heated bath. Their reaction with constituents of the bath thereforebegins immediately thereafter and proceeds in an extremely short time.Liquid materials may also be blown into the bath in a similar manner. Inthis case, the carrier gas simultaneously functions as an atomizingagent. If combustible reaction products in gaseous form escape from thebath during the performance of the metallurgical process, they may beburned by combustion agents such as air, oxygen-enriched air or oxygenintroduced directly above the bath and uniformly distributed over thesurface of the bath. Part of the heat thereby evolved is transferred tothe bath thereby obtaining a better utilization of heat.

The process of the invention permits several processes to be carried outin one operation In addition to metallurgical processes, processes of aphysical nature may be carried out. For example, the feed materials, ifnot introduced in liquid form into the reaction vessel, may first bemelted down and then the charge or constituents thereof, such as metaloxides, may be subjected to a reduction. This is followed by the blastrefining process and, finally, alloying additions may be introduced intothe bath. Of course, preparatory operations such as roasting,evaporation of volatile constituents, production of the slags suit ablefor the processes, and any other metallurgical process capable of takingplace in the liquid phase may be carried out.

The gaseous reaction products formed in carrying out the process arepreferably sucked off through heat exchangers and dry or wet dustseparators. In the heat exchangers, the gases give oif their sensibleheat for preheating the reaction media, for steam generation, or thelike. The dust separators free the gases from entrained dusts which areadvantageously returned into the metallurgical process. The cooled gasesfreed from dust are passed to further processing if utilizableconstituents are contained therein. Pollution problems are not to befeared when venting the gases into the atmosphere.

Several embodiments of the device for carrying out the process of theinvention are diagrammatically represented by way of example in theappended drawing. FIGS. 1 and 2 show a longitudinal cross-sectional viewand a cross-sectional view along the line AB, respectively, of areaction vessel in which the bath is imparted a spiral motion closed initself and taking place approximately about the circle of the center ofgravity of the producing cross-sectional area of the bath. Also providedare means permitting the combustible gaseous reaction products escapingfrom the bath to be burned directly above the bath. For heating up thereaction vessel or/ and the charge or for supplying the heatrequirements there are provided means for introducing fuels andcombustion agents. These means can also be optionally used forintroducing reaction media, fluxes, alloying materials and the likepresent in dustlike or fine-grained form.

The reaction vessel 1 holds a bath 2 of, for example, molten pig ironsupporting a layer of slag formed by limestone and ore. Air enrichedwith oxygen is blown in through nozzles 4 uniformly spaced apart overthe circumference of the reaction vessel and indicated in the drawing byarrows. These nozzles are positioned bliquely to the radius of the crosssection of the vessel. Their direction is tangential to an imaginaryconcentric circle 5 being smaller than the boundary line of the wall ofthe vessel 1. Most of the flow energy of the blast blown in istransferred to the bath which is imparted a vigorous agitation.Considering an infinitesimal bath element 6 and resolving its velocityvector 7 into 2 components S and 9 in the direction of the radius of thevessel and normally thereto first has the result that the bath element,seen as a projection on a horizontal plane, rotates about the verticalaxis of the vessel and simultaneously strives to the center of thevessel. Moreover, since a sucking action is produced at the openings ofthe nozzles 4 and behind them due to the flowing blast, the

bath is also imparted a rotary motion in the direction of the arrow 10about a horizontal axis 11. This axis is a circular line extending aboutthe vertical axis of the vessel and formed by about the center ofgravity of the producing bath cross-sectional area. From the pattern ofmotion of the bath there results the path of a bath element in a closed,spirally wound circular line about the vertical axis of the vessel andextending throughout the bath space. Due to the turbulent flow,secondary eddies are developed which are likewise uniformly distributedthroughout the bath so that a constant thorough agitation of the bath isobtained. The uniformly vigorous agitation of the bath aids the constantchange between the slag and the bath in a very efiicient manner so thatreactions between the two phases proceed rapidly and uniformlydistributed over the interface thereof.

The reaction gases emerging from the bath and principally consisting ofcarbon monoxide and nitrogen are burned with oxygen-enriched air blownover the bath surface through the nozzles 12 uniformly spaced apart overthe circumference of the reaction vessel and are led off from thereaction vessel through the waste gas outlet 13.

The nozzles 14 and 15 are provided for introducing fuels and combustionagents and optionally for introducing reaction media, fluxes, oralloying additions. They are alternately arranged and equidistantlyspaced over the circumference of the reaction vessel and directed ontothe bath surface at an angle of less than and preferably of 45 to 60.Moreover, they are positioned obliquely to the radius of the vesselsimilar to the nozzles 4. The fuels are introduced through the nozzles14 and the combustion media, e.g. air or oxygen, are introduced throughthe nozzles 15. The nozzles 14 may also be designed as burners throughwhich the fuel is blown into the reaction vessel together with thecombustion agent in the relative proportions desired. There is formed ahot flame with good turbulence which is brought into intimate contactwith the bath surface. If required, reaction media or'fiuxes influencingthe viscosity of the slag, ores or alloying additions in fine-grainedform are blown into the bath through the nozzles 15 by means of gaseousreaction media or inert carrier gases.

The functions of the different nozzles will be adapted to the particularrequirements and may be different from those described in the aboveexample. Thus, for example, reaction media, fluxes and the like may beintroduced into the bath through the nozzles 4 together with the blast.The functions of the nozzles 12, 14, and 15 may be exchanged at will ifrequired or appearing to be more favorable by the particular conditions.

For feeding the charge materials in molten or solid form, one or severalworking doors 16 are provided. The

discharge of the reaction vessel is effected through tap holes 17 forthe metal, e.g. steel, and through tap holes 18 for the slag. Severaltap holes, especially for the slag, are preferably arranged at differentlevels of the reaction vessel. The reaction vessel may also be providedwith a tilting device so that its content can be discharged in knownmanner'by dumping. In this case, the supply of the reaction media andmaterials to the nozzles is effected in conventional manner through pipelines extended through the supporting trunnions of the reaction vessel.

The nature of the lining of the reaction vessel is to be adapted inknown manner to the charge materials and the operating conditions.Depending upon the materials being processed, the lining is either madebasic, acid or neutral with consideration given to the operatingtemperatures encountered. A longer life can be achieved by cooling theouter wall. This purpose is served by a double jacket or a tubularsystem through which a cooling medium is circulated. Suitable coolingmedia include air, water, and other gases and liquids. The reactionvessel may also be constructed as a steam boiler.

The further embodiments represented in FIGS. 3 through 10 show severalselected arrangements of nozzles which are suitable for carrying out theprocess of the invention. They are limited to those nozzles which bringabout the agitation of the bath. All of the other devices alreadymentioned above have been omitted for better clarity.

FIG. 3 shows a longitudinal cross-sectional view of a reaction vessel 21and FIG. 4 shows a cross-sectional view of the same vessel taken alongthe line CD of FIG. 3. In this reaction vessel, the bath 22 ismaintained in agitation by introducing reaction media immediately abovethe bottom 23 of the vessel. Branch lines 25 for the reaction agentsextend from an annular line 24 to the nozzles 26 terminating obliquelyto the radii of the reaction vessel. The motion of the bath obtainablethereby is indicated by the arrows P and Q.

FIG. shows a longitudinal cross-sectional view of a reaction vessel 31and FIG. 6 shows a cross-sectional view of the same reaction vesseltaken along the line E-F. In this reaction vessel, the refining processis efiected by blowing the blast onto the bath 32 with the blowingdirection of the nozzles 33 being chosen at a steep angle and obliquelyto the radii of the reaction vessel. According y, the bath is imparted arotary motion (in the direction of the arrow P) and simultaneously arolling motion (in the direction of the arrow Q), which effects intimateagitation and by which new surfaces are constantly offered to the blast.

FIG. 7 shows a longitudinal cross-sectional view of a reaction vessel 41having a central introduction of the refining or reaction medium throughthe conduit 42, and FIG. 8 shows a cross-sectional view of the samereaction vessel taken a'ong the line GH of FIG. 7. The lower end of theconduit 42 terminates in nozzles 43 equidistantly spaced laterally atthe circumference of the conduit and terminating obliquely to the radiiof the vessel. The motion of the bath 44 is again indicated in thedrawing by the arrows P and Q. The line 42 may be arranged displaceable.With the nozzles positioned about halfway up the bath level there areobtained two superimposed rolling motions in opposite directions withsimultaneous rotation of the bath. With the nozzles positioned at ahigher level, the rolling motion is opposite to that represented in thedrawing. Whether the one or other position is preferable depends uponthe duration required of the contact between the bath and the blast.This is decisively influenced by the velocity of the reaction and theviscosity of the bath, both of which are generally dependent upon thetemperature. If, moreover, the nozzle-carrying conduit 42 is rotated,the rotation of the bath in the direction of the arrow P can beintensified.

If the nozzle-carrying conduit 42 is extended through a liftable coverof the reaction vessel, it is capable of being pulled out completely.The resulting opening may serve for charging and, in case of a tiltableconstruction of the vessel, for discharging.

FIG. -9 shows a longitudinal cross-sectional view of a reaction vessel51 and FIG. 10 shows a cross-sectional view of the same reaction vesseltaken along the line L-M of FIG. 9. Through the cover 52 of thisreaction vessel, blast lances which are capable of being displacedlengthwise and rotatable and equidistantly spaced over the circumferenceof the cover are sunk into the bath 54 from above. They may also bedesigned in such a manner as to terminate above the bath so that theblowing process is effected from above. Here again, the position of thenozzles in accordance with the invention produces the characteristicmotion of the bath indicated by the arrows P and Q. The cover 52 isliftable and may be pulled out and removed with the blast pipes, therebymaking the bath accessible. The discharge is effected by tilting thevessel.

The examples illustrated in the drawing are not complete. Anyconceivable combination of the embodiments described above is possiblewith consideration to be given to the nature of the processes to becarried out, the type of charge materials, etc.

Depending upon the type of materials being processed and the temperatureencountered, the nozzles are made of materials which withstand theseinfluences. If high temperatures are encountered, use is generally madeof nozzles made of steel or copper which are preferably studded andprovided with a coat of suitable material or slag present in carryingout the process. In the latter case, the nozzles are immersed in themolten slag. By water cooling, the nozzle becomes coated with a solidlayer of slag which is retained by the studs.

What is claimed is:

1. A method of effectively carrying out metallurgical processesincluding converting processes, which comprises injecting reaction mediainto a circular zone, containing a bath of molten raw materials, fromuniformly distributed sources with respect to the main axis of saidzone, forcing said media both in a rotary direction oblique to theradius of said zone and in a direction forming a tangency with said axisof said zone, whereby to maintain said bath in uniform turbulent motionsubstantially in rotary direction around said axis, and also forcingsaid media in a circular direction with respect to which said axis istangential, whereby to impart uniform distribution of said mediathroughout said bath.

2. A method according to claim 1, wherein a fuel is additionallyinjected into said zone being completely combusted therewithin.

3. A method according to claim 1, wherein a reducing fuel isadditionally injected into said zone being partially combustedtherewithin, the fuel additionally reducing the raw materials and thereaction media in said zone.

4. A method according to claim 1, wherein an additive material in finelydivided form is injected together with said reaction media by means of acarrier gas.

5. A method according to claim 1, wherein said reaction media is presentin finely divided form.

6. A method of effectively carrying out metallurgical processesincluding converting processes, which comprises injecting reaction mediainto a circular zone, containing a bath of molten raw materials, fromuniformly distributed sources with respect to the main axis of saidzone, forcing said media in a closed curve spiral direction which isoblique to the radius of said zone and to which the axis of said zone istangential, whereby to maintain said bath in uniform turbulent motionsubstantially in a rotary spiral direction around said axis and also ina circular direction with respect to which said axis is tangential, andto impart uniform distribution of said media throughout said bath,combustible reaction products forming in and emerging from the bathbeing burned with a combustible gas introduced from a source directlyover the bath and uniformly References Cited in the file of this patentUNITED STATES PATENTS Lane A112. 20, 1861 Bissau Oct. '2, 1383 JohnsonJune 19, 1888 Robert Dec. 25, 1888 Whiston July 15, 1952 Walker Jan. 21,1958 Allard et al Sept. 29, 1959

1. A METHOD OF EFFECTIVELY CARRYING OUT METALLURGICAL PROCESS INCLUDINGCONVERTING PROCESS, WHICH COMPRISES INJECTING REACTION MEDIA INTO ACIRCULAR ZONE CONTAINING A BATH OF MOLTEN RAW MATERIALS, FROM UNIFORMLYDISTREBUTED SOURCES WITH RESPECT TO THE MAIN AXIS OF SAID ZONE, FORCINGSAID MEDIA BOTH IN A ROTARY DIRECTION OBLIQUE TO THE RADIUS OF SAID ZONEAND IN A DIRECTION OBLIQUE TO THE RADIUS OF SAID ZONE IN A DIRECTIONFORMING A TANGENCY WITH SAID AXIS OF SAID ZONE WHEREBY TO MAINTAIN SAIDBATH IN UNIFORM TURBULENT MOTION SUBSTANTIALLLY IN ROTARY DIRECTIONAROUND SAID AXIS AND ALSO FORCING SAID MEDIA IN A CIRCULAR DIRECTIONWITH RESPECT TO WHICH SAID AXIS IS TANGENTIAL, WHEREBY TO IMPART UNIFORMDISTRIBUTION OF SAID MEDIA THOUGHOUT SAID BATH.